Metallurgical furnace.



U. WEDGE. METALLURGIGAL FURNAGE. APPLIGATION FILED FBB.25,1913.

Pamemd @$211914 METALLURG-IGAL F'RNACE.

Application ined February 25,

' which the following is a specification.

My invention relates to a furnace of the superposed hearth type havingrabbles which are carried by and depend from the hearths.

My invention relates particularly to a small furnace of this typeintended for lab oratory use, the objects of my invention being to soconstruct such a furnace as to' keep the cost of the same withinreasonable limits, to minimize the height of the furnace consideringthenumber of hearths therein, to provide simple and eiieient means forcarrying the hearths and for rotating such of the same as have to berotated; to provide for the ready insertion and removal of the rabbles;and to permit of the use of the furnace without discomfort in a closedroom.

The objects I attain in the manner hereinafter set forth reference beinghad to 'the accompanying drawing which represents a vertical sectional'View of a furnace constructed in accordance with my invention.

In the drawing, I have shown afurnace having nine hearths numberedconsecutively from top to bottom of the furnace, the hearths l, 3, 5, 7,and 9 being fixed hearths mounted in the outer wall of the furnace andthe hearths 2, 4, 6 and 8 beingrotatinghearths which are carried by acentral shaft l() mounted in a suitable step bearing below the furnaceand intended to be rotated by any suitable mechanism, j neferablj7 ofsuch character that the speed of rotation of the shaft can be changed atwill. rlhe furnace may, however, have a greater or less number ofhearths than I have shown.

The shaft l() is preferably hollow so as to permit of the circulation ofa cooling medium through it and it is surrounded bv relatively shortsleeve sections llinterposed between the successive rotating hearths soas to aid in the support of the same, said sleeves being composed offire brick, tile, or other heat-resisting material, in order to protectthe shaft from injury by the high temperatures which may have to bemaintained within the working chambers of the furnace. I

Speevcation of Letters Patent,

iPatenteol 2l?, fitti? 1.913, Serial No. 7,553,598.

rfhe outer wall of the furnace is composed of rings 12 ofl irebriclr,tile, or other refractory material made either in one piece or insections and interposed between the successive fixed hearths of thefurnace whereby'the building-up of a furnace structure having a closedcasing can be elfected expeditiously and with small expenditure of ytimeand labor..

ln order to restrict, as much as possible, the radiation of heat fromthe furnace, 'the outer wall-of the same is provided with a coatingorcovering -13 of magnesia, asbestos cement, or'other material which isa nonconductor or a poor conductor of heat.

The. lowermost of the rotating hearths of the furnace is mounted upon aflange or collar 14 on the shaft 10, and, where said shaft passesthrough the top and bottom fined hearths, it is provided with lutedjoints l5 to prevent the escape of gas from the interior of the furnaceat these points. rlhe top hearth of 'the furnace may conveniently beused as a, drying hearth, the material being fed inwardly over the sameby means of rabbles l@ carried by rabble arms 17 secured to andprojecting from the upper portion of the shaftlOr` the material beingfed from the drying hearth 1, onto the first rotating hearth 2 througl'ithe upper luted joint 15 and the course of the material in its pas sagethrough the furnace being then outwardly on the rotating hearths andinwardly on the stationary hearths, the rotating hearths being less indiameter than the interior of the furnace and the stationary hearthsbeing provided with central openings i8 of greater diameter than thesleeves ll in order to permit of the `dropping of the materialfromhearth to hearth. In order to provide for such n'ement of the materialover the hearths rabliles are provided, these rabbles having stemssupported in rabble holders which are mounted in openings in the fixedand rotating hearths and extend below the same so that the rabble stemscan be readily applied thereto, the. rabbles of one hearth actingupon-tlie material on the hearth below. The hearths may be soconstructed that the directioiifof travel of the material over the samewill be the reverse of that just described Without departing jinvention.

from any of the essential' features of my The rotating hearths are, bypreference, composed of rings of tile or other refractory material,.either in one piece or in sections, and the stationary hearths may becomposed of like rings. i

It is also advisable to provide the casing of the furnace at both theuppermost and lowermost chambers .thereof with a pipe or conduit for theintroduction of air or the escape ofthe gases dcvelopedin the furnace,the use of such conduit at each end of the furnace providing for theoperation of the latter with either updraft or downdraft.

When the rabbles are separate from the rabble holders, a rabble can bereadily changed by withdrawing it horizontally from engagement with therabble holder, removing it through a suitably located opening in theouter wall of the furnace, and inserting a fresh rabble in its place andthe rabble holder', after the removal of the rabe ble, can be liftedfrom its seat in the hearth into the chamber above the hearth fromvwhich it can likewise be withdrawn and a new one inserted in its place,whereas, if the rabble and rabble holder was made in one piece' thismethod of change could not be adopted and the furnace would have to bedismantled Whenever it became necessary to change the rabbles.

In a furnace of the type to which my invention relates. a great numberof hearths can be used without unduly increasing the height of thefurnace because said hearths can bevdisposed relatively close together,no

provision having to be made for the reception of rabble-Carrying arms inthe cham bers between the hearths.

The rabble holders may project below the hearths, as shown for instanceat Q0 and 20, Fig. l, so that the rabbles may be connected thereto byhorizontally separable joints, as shownrespectively at 19 and 19, or thejoints may be vertically separable as shown for instance at 19 and 20h,Fig. 1, or the rabbles may be applied directly to the hearth?,I in soulecases, as shown for instance at 19C, Fig. l, and the term depending fromsaid hearths is intended to apply either to the construction in whichthe rabbles are applied directly to the hcarths or indirectly throughthe medium of the rabble holders.

The central shaft may be stationary and the outer casing rotatable ifdesired, or one may be rotated in one direction and the other in theopposite direction, but the construee tion which l have heretoforedescribed is much to be preferred.

When vertically .separable couplings are einplojjcd bel we'en therabbles a nd ral'ible holdersy or lwarths that portion of the rabblewhich enters the coupling is of lesser ver- -tical dimensions` than thedistance between the' lbottom of the rabble and the hearth be-l neath sothatl the rabble may be first lowered to clear the coupling and then`Withdrzwm laterally from the chamber between the hearths, and therabble holders S20a are less in depth than the distance between theadjoining hearths to permit of vertical separation from the hearth belowand subsequent lateral removal from between said hearth and the hearthabove.

l claim 1. A metallurgical furnace having a central shaft and an outereasing, one rotatable in respect to the other, overlapping hearthscarried respectively by said central shaft and outer easing, and rabblesdepending from said hearths and serving to move the material over thesame.4 '4

2. A metallurgical furnace having a central shaft and an outer casing,one rotatable in respect to the other, hearths mounted alternately uponsaid central shaft and outer casing, and rings of refractory materialsurrounding said shaft and interposed between the hearths carriedthereby so as to protect the shaft from heat and also aid in the supportof the hearths..

3. A metallurgical furnace having alten nating fixed and rotatinghearths, a central rotatable shaft on which said rotating hearths aremounted, and rings of refractory material surrounding said shaft andinterposed. between the rotating hearths.

e. A metallurgical furnace provided with an outer casing and a centralshaft, onerotatable in respect to the other, hearths projecting inwardlyfrom said outer casing, and heart hs carried by and projecting outwardlyfrom said central shaft and alternating with the other hearths, saidouter casing being composed of rings of refractory material interposedbetween the hearths of said outer casing and serving to separate andsupport said hearths.

5. The combination, in a metallurgical furnace, of a series ofsupcrposed hearths acme of whichare rotatable in respect to the others,and rabble` depending from said hearths and separably coupled thereto,that portion of the rabble which enters the cou' p-ling being less invertical dimensions than the distance between the bottom of the rabe bleand the hearth beneath.

G. rlhe combination., in a metallurgical furnace, of alternating fixedand rotating hearths, with rabbles depending from said hearths, andrabble holdersv mounted in said heartl'is so as to be verticallyremovable therefrom, said rabble holders being of less depth than thespace between the hearth which carries them and the hearth above it andbeing in separable connection with the rabbles.

7. 'lhc cmnbination, in a metallurgical furnace of alternating fixed androtating hearths, with rabbles depending from said hearths, and rabbleholders mounted in said hearths so es o be vertically lemeyabe berefrom,said rabble holders being lees in depth than the space between thehearth. which oar l'es Vthem and the hearth above it, end the e abblesbeing so mounted in seid holders es to be horizontally separabletherefrom.

n testimony Whereoi have signed my l name to 'this Specification, inthe'presence of tw ,eubsemomg wltneeses.

UTL'EY WVDGE.

;messesi ,Yi/@TE A., "313mm, EMMIL'EON D., TURNER.

